CVE-2020-8553 : Security Advisory and Response

Kubernetes ingress-nginx Compromise of auth via subset/superset namespace names

Understanding CVE-2020-8553

This CVE involves a vulnerability in the Kubernetes ingress-nginx component that allows unauthorized users to compromise authentication via specific namespace names.

What is CVE-2020-8553?

The Kubernetes ingress-nginx component, before version 0.28.0, permits a user with certain privileges to overwrite the password file of another ingress using specific namespace or secret names.

The Impact of CVE-2020-8553

This vulnerability has a medium severity level with high confidentiality and integrity impacts. It requires high privileges and has a high attack complexity.

Technical Details of CVE-2020-8553

The technical details of this CVE are as follows:

Vulnerability Description

The vulnerability allows users to overwrite password files of other ingress objects using specific namespace or secret names.

Affected Systems and Versions

Affected Product: ingress-nginx
Vendor: Kubernetes
Vulnerable Versions: < 0.28.0

Exploitation Mechanism

The vulnerability can be exploited by a user with the ability to create namespaces and manipulate ingress objects.

Mitigation and Prevention

To address CVE-2020-8553, follow these steps:

Immediate Steps to Take

Upgrade Kubernetes ingress-nginx to version 0.28.0 or higher.
Restrict privileges for users creating namespaces and managing ingress objects.

Long-Term Security Practices

Regularly review and update access controls within Kubernetes environments.
Conduct security training for personnel to prevent unauthorized access.

Patching and Updates

Apply patches provided by Kubernetes for the ingress-nginx component.